CVE-2023-24035

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Timing Attack in Nagios XI Authentication

Publication date: 2026-09-14

Last updated on: 2026-09-22

Assigner: MITRE

Description

An issue was discovered in Nagios XI before 5.9.3. The is_insecure_login_authenticated function uses a insecure timing comparison that leads to an attacker being able to bruteforce the admin password, by measuring timing differences in the comparison.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-09-14

Last Modified

2026-09-22

Generated

2026-10-04

AI Q&A

2026-09-14

EPSS Evaluated

2026-10-03

NVD

CVE-2023-24035

EUVD

EUVD-2023-60635

Affected Vendors & Products

Vendor	Product	Version / Range
nagios	nagios_xi	to 5.9.3 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-208	Two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not.

Attack-Flow Graph

Executive Summary

This vulnerability is in Nagios XI versions before 5.9.3. It involves a timing attack due to an insecure comparison in the is_insecure_login_authenticated function. An attacker can exploit this by measuring timing differences during password authentication to brute force the admin password.

Detection Guidance

This vulnerability involves a timing attack on Nagios XI's admin password authentication before version 5.9.3. To detect it, check your Nagios XI version using the web interface or command line. If you are running a version older than 5.9.3, the system is vulnerable. No specific commands are provided in the context to actively detect the vulnerability on your network.

Impact Analysis

An attacker could gain unauthorized access to the Nagios XI admin account by brute forcing the password. This could allow them to view sensitive system information, modify configurations, or disrupt services.

Compliance Impact

This vulnerability allows brute-forcing admin passwords through timing attacks, which could lead to unauthorized access to sensitive data. This may violate compliance requirements under GDPR (data protection) and HIPAA (healthcare data security) by enabling unauthorized access to personal or health information.

Mitigation Strategies

Upgrade Nagios XI to version 5.9.3 or later to address the insecure timing comparison vulnerability in the admin password authentication process.

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